Implement more accurate fix for MC-183518

The game now sleeps precisely till the next tick, rather than still
waking up periodically

Co-authored-by: HaHaWTH <[email protected]>

Author: embeddedt

common/src/main/java/org/embeddedt/modernfix/common/mixin/perf/fix_loop_spin_waiting/BlockableEventLoopMixin.java

@@ -0,0 +1,48 @@
+package org.embeddedt.modernfix.common.mixin.perf.fix_loop_spin_waiting;
+
+import com.llamalad7.mixinextras.injector.wrapoperation.Operation;
+import com.llamalad7.mixinextras.injector.wrapoperation.WrapOperation;
+import net.minecraft.Util;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.util.thread.BlockableEventLoop;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.Unique;
+import org.spongepowered.asm.mixin.injection.At;
+
+import java.util.concurrent.locks.LockSupport;
+import java.util.function.BooleanSupplier;
+
+@Mixin(value = MinecraftServer.class, priority = 500)
+public abstract class MinecraftServerMixin extends BlockableEventLoop<Runnable> {
+    @Shadow private long nextTickTime;
+
+    protected MinecraftServerMixin(String name) {
+        super(name);
+    }
+
+    @Unique
+    private boolean mfix$isWaitingForNextTick = false;
+
+    @WrapOperation(
+            method = "waitUntilNextTick",
+            at = @At(value = "INVOKE", target = "Lnet/minecraft/server/MinecraftServer;managedBlock(Ljava/util/function/BooleanSupplier;)V")
+    )
+    private void managedBlock(MinecraftServer instance, BooleanSupplier isDone, Operation<Void> original) {
+        try {
+            this.mfix$isWaitingForNextTick = true;
+            original.call(instance, isDone);
+        } finally {
+            this.mfix$isWaitingForNextTick = false;
+        }
+    }
+
+    @Override
+    protected void waitForTasks() {
+        if (this.mfix$isWaitingForNextTick) {
+            LockSupport.parkNanos("waiting for tasks", (this.nextTickTime * 1000000L) - Util.getNanos());
+        } else {
+            super.waitForTasks();
+        }
+    }
+}